It is recommended to give BCTip in addition to the regular tips
At the Crypto Currency Conference this past weekend there was an event on Friday at BitPay's offices and they had a tablet set up so tips in Bitcoin to the bartenders could be accepted:

However, ... the bartenders were serving customers faster than tippers were tipping -- (and who wants to stand there sending a tip after you finally got booze in your hands anyways), so having some BCTips with me really would have been useful. I wish I had thought to print some up ahead of time.
And then the cocktail hour on Saturday evening had only a regular tip jar, so there was no bitcoin tipping (though the bartender said she had plenty of people ask to give bitcoin tips). There too these BCTips would have come in handy! i did have a paper wallet funded with some tip-sized amount and offered to give that as a tip but the process to redeem it (i.e., installing an app, sweeping the funds, etc.) was beyond what the bartender wanted to hear.
There's definitely a place for these!